A variety of consumer products available today rely upon the use of wireless communication. Microsoft Corporation has developed a product called "ACTIMATES BARNEY," which is an educational computer product for young children. The "ACTIMATES BARNEY" product includes animated educational programs and animated electronic characters that move and speak. The animated electronic characters are capable of receiving control data and speech data from a control system and responding by sending status and sensor data to the control system. When the child is using the program, an animated electronic character "comes to life" and interacts with the user and with characters that are displayed on a display device. The animated electronic character acts as a guide or friend to the child and provides assistance, encouragement, and guidance as the child uses the program. The animated electronic character moves and speaks in response to signals that are retrieved from the educational program's storage medium and transmitted to the animated electronic character. The animated electronic character also includes various sensors for receiving input signals from the child.
Because the child physically interacts with the animated electronic character, the character can easily be mishandled resulting in the mechanical and electrical components being damaged. Mishandling may also be in the form of external forces being applied to an appendage or other movable part such as the character's arms, legs, eyes, or head. For example, the child may block or forcibly move the appendage while a motor is trying to move it. If the force is large enough, the appendage may break. In addition, the child may drop or toss the character, which can likely damage the servos within the character.
Some prior art devices address the problem of external forces by employing slipping mechanisms. Specifically, if the child blocks the moving appendage, the appendage slips relative to the motor. Such slipping mechanisms include a rubber band between a servo and an output shaft of a motor or a clutching device with a mechanical slipping disk similar to those used in a cassette player. In addition, some devices use a belt and pulley system, which is another type of slipping mechanism. One disadvantage of using slipping mechanisms is when the appendage slips, synchronization is lost between the appendage and the motor. Thus, the appendage is unable to reposition itself or move to the originally desired position.
Generally, these devices may have some type of indexing feature, such as a hole in a gear, to electronically determine the relative position of the appendage. However, if the appendage slips, the electronics can detect the slippage, but there is no mechanical mechanism to correct the slippage. These devices do not have a self-alignment feature. To provide such a feature can be expensive, complex, and difficult to manufacture.
In addition, in battery-operated devices, typically, there is no feature to control the power to the device should the child obstruct the appendage. Power is continually supplied as the appendage tries to move to the desired position regardless of whether there is an external force preventing it from doing so. Hence, batteries are likely to run down quickly, thereby requiring replacement on a frequent basis.
Therefore, there is a need to provide an animated electronic toy that is robust and able to withstand repeated mishandling. There is also a need to provide an animated electronic toy that is able to withstand external forces regardless of whether the animated electronic toy is trying to articulate or move an appendage or other movable part. In addition, there is a need to provide a self-alignment feature for an appendage or movable part to prevent damage to the servo when an external force is applied to the appendage or movable part. There is also a need to provide a self-alignment feature for an appendage or movable part so that when external forces are applied to the appendage or movable part, the appendage or movable part is able to move to the position that it would have moved to if the external force was never applied. Furthermore, there is a need to provide a power management feature to conserve power consumption when an obstruction is present. There is a further need to provide a design that provides these capabilities while being easy to manufacture. Finally, although the technology and capabilities of an animated electronic toy such as this are quite complex and sophisticated, there is a need to provide these capabilities at a low cost.